Human/Animal embryos

A genetic fragment of Australia’s extinct Tasmanian tiger has been brought back to life by Melbourne researchers.

Dr Andrew Pask and Professor Marilyn Renfree from the University of Melbourne have inserted part of a gene involved in bone growth from the fabled animal into mice, and confirmed that it functioned.

"We’ve brought a fraction of this extinct genome back to life," Pask, at the Department of Zoology, says. "No one has done this in a living organism before."

The Tasmanian tiger or thylacine (Thylacinus cynocephalus) was a large, meat-eating native Australian marsupial that was hunted to extinction in the wild in the early 1900s.

The last-known animal died in captivity in the Hobart Zoo in 1936.

The latest breakthrough, which is published this week in the journal PLoS One, is the culmination of nine years of effort by the team.

PreservedIn 1999, the team gained access to tissue samples from young Tasmanian tigers that had been preserved in alcohol 90 years’ earlier and were in the Museum Victoria collection in Melbourne.

Painstakingly, the researchers went about extracting the DNA from the samples.

"It took us quite a long time," says Renfree, the deputy director of the Australian Research Council Centre for Excellence for Kangaroo Genomics.

Eventually, Renfree and Pask were able to isolate small regions that they pieced together to provide the sequence of several genes.

One of these was the proα1(II) collagen (Col2a1) gene, which is involved in making bone.

The Melbourne researchers and their colleague, Professor Richard Behringer from the MD Anderson Cancer Centre at the University of Texas in the US, were then able to take the "enhancer" region of this gene and insert it into the genomes of mouse embryos, using a genetic delivery method known as a plasmid.

Subsequently, they showed that the mice were producing the collagen using the thylacine gene fragment.

‘Extinction isn’t forever’This is the first time that DNA from an extinct species has been used to induce a functional response in another living organism, Renfree says.

"It shows that extinction isn’t forever, at least if you’re a gene," she says.

A separate, much publicised attempt by the Australian Museum to clone the Tasmanian tiger back from extinction was scrapped in 2005.

But despite the latest results, Renfree says it is "highly unlikely" that the entire animal can be resurrected in this way.

Still, the latest work shows it is possible to study the functions of genes from extinct species, she says.

"It tells you a lot about the evolution of these genes and of these animals," she says.

Let’s hope these practices don’t get into the whitehouse! I can only imagine a Dick Cheney attack dog that will not only bite you in the face, but shoot you in the face too. And then make you apologize for the trouble the event caused him and his family…

Little known fact: Mickey Mouse was actually "Mickey O’Mousihan," a small-time hood from South Boston, before he was discovered. Rumor has it that Mickey worked the docks, and killed at least three men with a shiv he’d fashioned out of an old toy golf club.

… but this has already happened in the U.S. We, scientists, have created chimera mice, mice with human genes, fish with human genes, and even flies with human genes (I took part in that research). The take home lesson from this type of research is that many eukaryotic genes are almost completely swapable between species and on a cellular level humans and mice are nearly identical.